Welcome Guest! If you are already a member of the BMW MOA, please log in to the forum in the upper right hand corner of this page. Check "Remember Me?" if you wish to stay logged in.

We hope you enjoy the excellent technical knowledge, event information and discussions that the BMWMOA forum provides.
Why not take the time to join the club, so you can enjoy posting on
the forum, the club magazine, and all of the discounts and benefits the BMWMOA offers?Want to read the MOA monthly magazine for free? Take a 3-month test ride of the magazine; check here for details.

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You will need to join the MOA before you can post: click this register link to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

NOTE. Some content will be hidden from you. If you want to view all content, you must register for the forum if you are not a member, or if a member, you must be logged in.

2004 R1150RT Wideband O2 Sensors

I'd like to get some inputs on wide-band O2 sensors for the R1150RT.

As I understand it, under cruise conditions, constant TPS and roughly constant RPM, the Motronic 2.4 goes into Closed Loop operation, cycling between slightly rich and slightly lean with the engine running with an average AFR (air fuel ratio) of 14.7 to 1 as set by the narrow band O2 sensor and Motronic.

Digressing for a moment, in the aircraft that I flew for many years the level flight cruise setting (for a given propeller speed) was to lean the fuel flow until peak EGT (exhaust gas temperature) was achieved; or to lean to peak EGT and then richen the mixture by 25 to 50 degrees F. Peak EGT gave maximum aircraft range, and Peak EGT minus 25 degrees (or so) gave maximum speed (cruise power). (Peak EGT - 25F was also considered kinder to the engine since it was running a bit cooler.)

So if I've got it about right, when I'm cruising on an R1150, the narrow-band O2 sensor is "leaning" the engine to peak EGT and something less than best cruise power for a given condition. That being the case, I'm not surprised that the engine must be carefully tuned and balanced so that it doesn't "surge" from a bit of imbalance (one cylinder being slightly leaner than the other).

Although my particular RT seems to run well, I've got this sense that it would like to sip a bit more fuel while cruising. The BoosterPlug I installed has added some fuel to Open Loop operation but when cruising, Closed Loop O2 operation leans things right back to peak EGT--14.7:1 AFR.

One of the options for richening cruise is to keep the Motronic out of Closed Loop operation by removing or changing the CAT plug to one that tells it that there isn't a catalytic converter. But I'm not sure what AFR or EGT I'd end up with.

So like the blind squirrel looking for a nut, I've been trying to find a plug-n-play replacement for the stock narrow-band O2 sensor or a way to shift it. Today I came across the Innovate Motorsports LC-1 Wideband O2 Sensor.

As I read it, the LC-1 can be used as an Air Fuel meter or as replacement for the stock O2 sensor that can have its AFR programmed over a wide range. In this mode, one of its outputs is in the 0V to 1V range, the same as the stock narrow band O2 sensor.

I've searched this forum and others and can't find a whole lot on the LC-1. Has anyone tried this out on an R1150? What has been your experience? I'd appreciate any thoughts or comments.

Hi Roger,
Just un-plug the O2 sensor and leave code plug alone. The '04 computer isn't too sophisticated and bike will run fine with inputs from remaining sensors like air temp and oil temp affecting the fuel mixture. It would be a different story on new machines with O2 sensors after the cat.

I disconnected mine and saw a vey slight drop in fuel economy but no real improvement in performance. I might also add that I removed the cat from the stock exhaust system many moons ago so disconnecting the O2 sensor would not harm what isn't there.

I dinked around with different code plugs and decided on the green code plug so that is what I use. Green results in a slightly richer mixture and smoother performance, at least for my bike.

Hi Roger,
Just un-plug the O2 sensor and leave code plug alone. The '04 computer isn't too sophisticated and bike will run fine with inputs from remaining sensors like air temp and oil temp affecting the fuel mixture. It would be a different story on new machines with O2 sensors after the cat.

I disconnected mine and saw a vey slight drop in fuel economy but no real improvement in performance. I might also add that I removed the cat from the stock exhaust system many moons ago so disconnecting the O2 sensor would not harm what isn't there.

I dinked around with different code plugs and decided on the green code plug so that is what I use. Green results in a slightly richer mixture and smoother performance, at least for my bike.

Thanks, I hear you. I guess a lot have taken that approach. I'd like to keep the catalytic converter. From what I've seen on this site and others: grounding pin 86 says low octane, grounding pin 87 indicates a cat converter, and 87a says its an RT-ish bike (not positive about 87a). The pink '04RT plug is what I've got.

I'm planning to keep the converter and plug stock but shift the closed-loop mixture a bit richer. From GS-911 data I've logged while riding, the motronic spends at least half it's time closed-loop.

If you buy the LM-1 & watch the meter, you can see your bike flip flop when in closed loop (sticking probe in tailpipe), I don't think changing yoru O2 to a wideband will work with your computer, which is not programmed to use that input. The narrow band as I understand it just flip flops back & forth as the computer adjusts in closed loop. goes lean, adds a bit more fuel, goes rich, takes a bit out, over & over again, fairly quickly.

If you buy the LM-1 & watch the meter, you can see your bike flip flop when in closed loop (sticking probe in tailpipe), I don't think changing yoru O2 to a wideband will work with your computer, which is not programmed to use that input. The narrow band as I understand it just flip flops back & forth as the computer adjusts in closed loop. goes lean, adds a bit more fuel, goes rich, takes a bit out, over & over again, fairly quickly.

Thanks for the feedback. The flip-flopping can also be seen on the GS-911 I'm using. What have you thought of the quality of the LM-1?

I've found five different options for wideband O2 sensors with Programmable Narrow Band secondary outputs. Although the wideband primary outputs can't drive the Motronic 2.4 in the '04 RT; if properly grounded, the programmable Narrow Band outputs can.

The above 5 products require 12 volts and ground, include a Bosch Wideband O2 Sensor and have Narrow Band outputs that can be programmed to switch AFR from less than 10:1 up to nearly 20:1, much more range than I'm looking for. All require a computer with Serial Port to set the switching AFR. I would start at 14.7:1 (stock setting) and step down slowly, monitoring results.

Also, the Power Commander III USB has a wideband sensor included. As everyone here knows, the PC III interfaces at both injectors, at the TPS and at the O2 sensor which gets replaced. The stock O2 is removed and the PC III, using a wideband O2, takes over the Closed Loop function from the Motronic. Their "stock" fuel maps initially set the Closed Loop AFR to 13.8:1 (compared to 14.7:1).

To keep things simple, and giving the BMW/Motronic designers due respect, I'm planning on the simplest approach, either the MXT-L or ZT-3. So far Zeitronix has been more responsive to my questions. I'm still undecided.

This may seem like a big effort for a small shift of Closed Loop AFR, but as I mentioned in the OP, reducing the Closed Loop EGT by 25 to 100 F in my flying experience has a positive effect on performance.

Yesterday I plugged in my GS-911 Diagnostic Tool, interfaced it to a small Netbook PC via Bluetooth and took some rides to gather data after the bike warmed up. On the first couple rides I lost the Bluetooth connection but the third time I got some useful data by bungy-cording the PC to the rear seat.

The bike was fully warmed up at the start. Here are the results:

Length of ride: About 15 minutes.
Course: Winding, hilly local roads.
Gears/Speeds: All six gears, many speed and gear changes, from Wide Open to Closed Throttle, up to 70 MPH

Data Points: A little over 1,000 sets of data of all functions logged by the 911 during the 15 minute ride.
RPM: 1100 to 5500;

Tank Venting: Tank venting was enabled by the Motronic about 3 minutes into the ride, then on for 5 minutes, then off for three minutes, then on again. (I included this just because I found it interesting.)

Fuel Pump: On all the time, as expected

And now the data I was looking for:
Closed Loop operation: The Motronic was Closed Loop 48% of the ride, as I mentioned, it was a winding hilly, many gear and throttle change trip. On a highway trip I would expect a higher percentage of closed loop operation, perhaps tomorrow I'll give that a try.

What this tells me is that no matter what other change you make to the motorcycle, the Motronic will be insisting on an AFR between 14.5 and 15 to 1 (approx), and be centered on a lean 14.7:1 most of the time.

I don't know what results I'll get, but it looks worth giving a programmable Narrow Band O2 sensor a try.

Compared to the Lower RPM run in the previous trip Closed Loop time was much less 25% (higher average RPMs) vs 55% (lower RPMs). Many posters here and other places recommend running the R1150RT at higher RPMs, this has the effect of running a richer average AFR because the motorcycle is Open Loop.

Also, I felt that the bike is "stronger" when it is cold. That feeling makes sense given that it stays Open Loop with richer mixtures until the engine temp reaches (about) 115F. (Wonder if it stays Open Loop if I put a fixed resistor on the Oil Temp Sensor?)

If anyone has an old and/or dead R1150RT O2 Sensor, please PM me. I would like to purchase it for the connector so that I can build a Wide Band replacement system. Thanks.

Hello Roger,
This data is interesting. A resistor in series with the oil temp sensor, hmmmm. Would the oil temp sensor be the same one that supplies the input to the dash board oil temperature gauge? If you want to always run open loop why not just unplug the O2 sensor? I tried this and the only difference in actual operation I could detect was I lost about 2 mpg. Of course I'm one of these guys that never rides below 4K RPM and in 38K miles my 6th gear is like new.

Hello Roger,
This data is interesting. A resistor in series with the oil temp sensor, hmmmm. Would the oil temp sensor be the same one that supplies the input to the dash board oil temperature gauge? If you want to always run open loop why not just unplug the O2 sensor? I tried this and the only difference in actual operation I could detect was I lost about 2 mpg. Of course I'm one of these guys that never rides below 4K RPM and in 38K miles my 6th gear is like new.

Yeah you're right about the Oil Temp Sensor. It was more a question about how the bike would perform, and it would be richer by an unknown amount. Removing the O2 and catalytic converter is another way to get an unknown richer mixture.

There has been tons written about "surging" and how to get the Boxer engine to perform as well as it can on a 14.7:1 AFR -- TBB, Valve Adjustments, Dual Spark, Zero=Zero, BoosterPlug, etc. That good work has made the R1100s and R1150s very rideable but maybe not the best it can be. The question in my mind is:

Now that I'm getting the data, and given how much time the bike spends Closed Loop, how would the R1150RT run with a Closed Loop ratio of 14.5:1 or 14.3:1? Maybe there is a point that would still allow it to be closed loop, run "stronger", and still keep the catalytic converter in the game.

I also wonder what the effect of eliminating the "shutting off" of injectors on deceleration would have. I'm on shaky ground there, no real idea.

I think if you didn't shut off the injectors when throttle is closed you might wash down the cylinders a bit, who knows and how would you know one way or another. I think the one thing that really smoothed out my machine was removing the throttle bodies and giving them a really good cleaning. Going to do this once a year. Oh, not shutting off injectors might result in back firing as well.

Oh, I cut my teeth in '76 on my first beemer, a '77 R75/7. These big flat twins like to rev. I don't mean popping the clutch with a big handful of throttle either just nice revs while cruising. If I could buy a lower ratio FD for my 1150 I would. Then I could use 6th gear now and then. Just got through doing a FD change from 32-11 to 34-11 tooth on my '81RT and now I can use 5th. Gave it a good spline lube and swing arm bearing clean and repack, life's good.

As for the quality of the Innovate products, they are very high quality. Many of the aftermarket companies that make tuning tools & computers use their technology. Those include Racepak, AEM, Edelbrock I think still uses it.

As for the quality of the Innovate products, they are very high quality. Many of the aftermarket companies that make tuning tools & computers use their technology. Those include Racepak, AEM, Edelbrock I think still uses it.

I could see using an LC-1 with the gauge you could mount.

Thanks for the feedback on Innovate. Their website forum makes it seem like the products are hard to use. But it is my choice at the moment.

There's a good package price now on the LC-1 with gauge. Now the same price as the MTX-L. I'm trying to find a dead O2 so I don't have to cut into my working unit.